Re: [PATCH 15/25] power: reset: Add basic power reset driver for RDA8810PL

[Krzysztof Kozlowski <krzk@kernel.org>]

On 17/09/2025 22:25, Dang Huynh via B4 Relay wrote:
> From: Dang Huynh <dang.huynh@mainlining.org>
> 
> This basic driver can only reboot, powering off requires the modem
> firmware which we don't have yet.
> 
> Signed-off-by: Dang Huynh <dang.huynh@mainlining.org>
> ---
>  MAINTAINERS                      |  6 +++++
>  drivers/power/reset/Kconfig      |  9 +++++++
>  drivers/power/reset/Makefile     |  1 +
>  drivers/power/reset/rda-reboot.c | 58 ++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 74 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index cbe2ab8af6dcd40dd1456d9df55673dace3c87b2..5ec24d8657bffb55c160947a930980e428c6a6b7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21399,6 +21399,12 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/clock/rda,8810pl-apsyscon.yaml
>  F:	drivers/clk/rda/clk-rda8810.c
>  
> +RDA MICRO MODEM RESET DRIVER
> +M:	Dang Huynh <dang.huynh@mainlining.org>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/power/reset/rda,md-reset.yaml
> +F:	drivers/power/reset/rda-reboot.c
> +
>  RDA MICRO REAL TIME CLOCK DRIVER
>  M:	Dang Huynh <dang.huynh@mainlining.org>
>  S:	Maintained
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index 77ea3129c70806929f3c248667db42f05f5f1d27..de9b1afb94d14a5d23286ddb302af4107d649c12 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -205,6 +205,15 @@ config POWER_RESET_QNAP
>  
>  	  Say Y if you have a QNAP NAS.
>  
> +config POWER_RESET_RDA
> +	bool "RDA Micro Reset Driver"
> +	depends on ARCH_RDA

|| COMPILE_TEST
everywhere, for all your drivers.

> +	help
> +	  This driver supports soft resetting RDA Micro boards by writing
> +	  magic values to the modem register.
> +
> +	  Say Y if you have a board with RDA Micro SoC.
> +
>  config POWER_RESET_REGULATOR
>  	bool "Regulator subsystem power-off driver"
>  	depends on OF && REGULATOR
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index b7c2b5940be9971548a5527384d1931abff11c4c..14371230410dad2852489160f4fc23d8fd087d6e 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_POWER_RESET_ODROID_GO_ULTRA_POWEROFF) += odroid-go-ultra-poweroff.o
>  obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
>  obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
>  obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
> +obj-$(CONFIG_POWER_RESET_RDA) += rda-reboot.o
>  obj-$(CONFIG_POWER_RESET_REGULATOR) += regulator-poweroff.o
>  obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
>  obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o
> diff --git a/drivers/power/reset/rda-reboot.c b/drivers/power/reset/rda-reboot.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..d87b063ba67d847f8e869e50a6c01427b2866889
> --- /dev/null
> +++ b/drivers/power/reset/rda-reboot.c
> @@ -0,0 +1,58 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2025, Dang Huynh <dang.huynh@mainlining.org>
> + *
> + * Based on drivers/power/reset/msm-poweroff.c:
> + * Copyright (c) 2013, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/reboot.h>
> +#include <linux/pm.h>
> +#include <linux/mfd/syscon.h>
> +
> +static void __iomem *rda_md_sysctrl;

No, no singletons.

> +
> +static int do_rda_reboot(struct sys_off_data *data)
> +{
> +	/* unprotect md registers */
> +	writel(0x00A50001, rda_md_sysctrl);
> +
> +	/* reset all */
> +	writel(0x80000000, rda_md_sysctrl + 4);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int rda_reboot_probe(struct platform_device *pdev)
> +{
> +	rda_md_sysctrl = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(rda_md_sysctrl))
> +		return PTR_ERR(rda_md_sysctrl);
> +
> +	devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART,
> +				      128, do_rda_reboot, NULL);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id of_rda_reboot_match[] = {
> +	{ .compatible = "rda,md-reset", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, of_rda_reboot_match);
> +
> +static struct platform_driver rda_reboot_driver = {
> +	.probe = rda_reboot_probe,
> +	.driver = {
> +		.name = "rda-reboot",
> +		.of_match_table = of_match_ptr(of_rda_reboot_match),


Drop of_match_ptr, you have warnings here.

> +	},
> +};
> +builtin_platform_driver(rda_reboot_driver);
> 


Best regards,
Krzysztof